This invention relates to a capsule for making beverages. In particular reference is made to those capsules comprising a body and a lid which closes the top of the body and in which a powdered food substance (for example coffee powder) is positioned, which can be extracted by passing water (which may be pressurised) through it to make a beverage, for example coffee. More specifically reference is made to those capsules in which the body comprises a lower wall and a side wall which form a chamber in which a rigid or semi-rigid filter is positioned.
In more detail, reference is made to those capsules suitable for use in beverage making systems in which the capsule is pierced at the lid, to allow the injection of water (which may be pressurised) into the capsule itself, and at the lower wall, to allow dispensing outside the capsule of the beverage produced by the interaction of the water with the powdered food substance.
In such capsules the filter is substantially a flat filter, normally disk-shaped, positioned close to the lower wall of the capsule body and separates the powdered food substance from the lower wall in such a way that powder does not come out of the capsule after a piercing element has penetrated through the lower wall. In fact, the filter comprises openings which allow the beverage to pass through it in such a way that said beverage can come out of the capsule through the lower wall (through the hole made by the piercing element or through a channel present in the latter). However, at the same time the openings allow the powdered food substance to be retained.
However, this prior art technology may have several disadvantages under certain circumstances.
In particular, with some types and particle sizes of the powdered food substance the prior art capsules may not allow optimum extraction of the powdered food substance. In fact, for example, the beverage made by the interaction between the water and the powder located close to the lid, in order to be able to come out of the capsule must reach the filter and therefore must pass through all of the powder below which may obstruct its path. In fact, once moistened with the water, the powdered food substance tends to become compacted, obstructing the flow of the liquids which encounter increased resistance to permeation through the powder.
In fact, the water injected into the capsule tends to draw the powdered food substance with it, carrying it towards the filter and causing it to build up and become compacted precisely at the filter, therefore increasing the resistance of the powdered food substance to the passage of liquids through it and resulting in difficulties draining the beverage through it.
Therefore, during the injection of water into the capsule, areas are created in the powder which are compacted to different degrees. Therefore, prior art capsules have the disadvantage that the powdered food substance can only be permeated unevenly, that is to say, to drastically different degrees depending on the position of the powdered food substance in the capsule. Moreover, in prior art capsules, since the water tends to flow in the zones of the powder which are less resistant to permeation, preferential channels for the passage of the water are easily created, the result being that the powdered food substance is not all permeated homogeneously.